(1) Field to Which Invention Relates
The invention relates to an electrolytic cell for the treatment of water, more particularly for the purification of water; it relates in particular to a multi-pole elctrolytic cell, which can be used in the most varied fashions for the treatment, and more particularly for the purification of water and comprises a closed container with a lower inlet opening and an upper outlet opening for the water and at least two electrodes, which are adapted to be connected with the positive and the negative pole of a DC source.
(2) The Prior Art
The most varied types of electrolytic methods for the treatment, and more particularly the purification of water, particularly the preparation of drinking water, have been proposed. With these known methods it is possible to remove the dissolved and suspended contaminating materials comprised in the water to be treated or purified electrolytically. This is generally carried out using an electrolytic cell in such a manner that consumable aluminum or iron electrodes are used to supply aluminum or iron ions to the water and which under the conditions of electrolysis form aluminum hydroxide and, respectively, iron hydroxide, which is flocculated out and entrains with it the contaminating materials present in the water by adsorption or inclusion. In this manner it is not only possible to remove the solids comprised in the contaminated water but it is also possible to remove dissolved contaminating substances and any discoloration which may be present.
In order to kill any micro-organisms which may be present in the contaminated water it is possible to add silver or copper ions to the water by making use of consumable silver or copper electrodes in order to bring about the death of the undesired germs. It is also possible to disinfect water for private and public swimming baths, and more particularly water for drinking purposes by adding disinfecting chemicals or producing electrolytically elementary chlorine or ozone or, respectively, per-compounds within the water to be disinfected.
A feature possessed by all the above described methods for cleaning and disinfection of water, more particularly of drinking water is that they are very complicated as regards the apparatus required and are also expensive and are extremely liable to breakdown. Thus, for example, in the case of the use of consumable aluminum, iron, copper or silver electrodes, for the introduction of aluminum, iron, copper or silver ions into the water to be treated, there is the disadvantage that the metal electrodes used for this purpose have to be cleaned or even completely replaced after only a few hours of operation, because a coherent oxide film (oxide crust) is formed on a surface and which interferes with further electrolytic treatment of the water. Thus, for example, in the case of the use of an aluminum anode the aluminum oxide film insulates the surface of the anode from the surroundings so that higher and higher voltages for electrolysis are necessary and which lead to the formation of more and more oxygen instead of aluminum ions. In the case of the use of an iron anode an iron oxide film coating is also formed within a few hours. This film is admittedly a comparatively good electrical conductor but further electrolysis takes place more and more on the iron oxide film surface with the formation of more and more oxygen instead of iron ions. In the case of the use of a copper or silver anode there is also the formation of an undesired oxide film coating, which prevents the formation of copper and silver ions during electrolysis.
Apart from the above mentioned difficulties in the case of previously used electrolytic cells there are the additional disadvantages that the electrodes, which are generally arranged parallel to each other, are completely unevenly consumed and used up so that the operation of the electrolytic cell is interfered with even long before the electrodes are completely consumed. Furthermore, in the case of previously proposed electrolytic cells there is an undesired corrosion, more particularly at the positions at which the electrodes are fixed and are electrically connected with the external current source.